1. Field of the Invention
The present invention relates to an improvement on a camera of the kind having a frame-position detecting means arranged such that, when the camera is loaded with a film cartridge containing a half-way exposed film therein, the frame-position detecting means detects the leader position of unexposed frames of the film during transportation of the film from the film cartridge by actuating a reproducing means to detect the presence or absence of magnetic signals and automatically sets an unexposed frame at a predetermined photographable position.
2. Description of Related Art
Cameras of the kind having a magnetic head and arranged to be capable of recording, with the magnetic head, data of varied kinds at a predetermined position of a magnetic recording layer provided at every photo-taking frame of a film have been commercialized during recent years. The data thus magnetically recorded is read at a photofinishing laboratory while the film is in process of printing, and is then used either as reference data for improvement in quality of prints or is printed on the surface or reverse side of printing paper.
In addition to the above-stated usage, the magnetic data is used also for detecting a boundary position between an unexposed frame and an exposed frame in a case where a film cartridge which is taken out from a camera in a half used state before complete use thereof is to be used later for further photographing. The magnetic data is usable for this purpose, because the magnetic data is normally recorded at a predetermined position at each exposed frame. Therefore, the boundary position between an unexposed frame and an exposed frame can be detected by searching for the presence or absence of the magnetic data by means of the above-stated magnetic head. A leader position searching (detecting) function is carried out in this manner. Hereinafter, this function will be called an MRC (Mid Roll Change) function.
However, accurate detection of the presence or absence of the magnetic data is sometimes hindered by the intrusion of a noise into the magnetic head and a magnetic signal detecting part or circuit due to some external factor while execution of the MRC function is in process.